kubectl Essentials — Kubernetes Tutorial

Everyday commands

kubectl get pods                      # list (add -A for all namespaces, -o wide for more columns)
kubectl describe pod web-7d9f8        # details and recent events
kubectl apply -f deploy.yaml          # create or update from a file (declarative)
kubectl delete -f deploy.yaml
kubectl logs deploy/web --tail 50     # logs (-f to follow, --previous after a crash)
kubectl exec -it web-7d9f8 -- sh      # a shell in a container
kubectl explain deployment.spec.strategy   # built-in API documentation

Output formats

-o yaml, -o json, -o jsonpath='{.status.phase}' and -o custom-columns=... turn kubectl into a scripting tool. Use kubectl apply with files in Git rather than imperative create/edit for anything that lasts.

kubectl create namespace demo-kubectl > /dev/null trap 'kubectl delete namespace demo-kubectl --wait=false > /dev/null' EXIT kubectl -n demo-kubectl create deployment web --image=nginx:1.29-alpine > /dev/null kubectl -n demo-kubectl rollout status deployment/web --timeout=120s > /dev/null kubectl -n demo-kubectl get deployment web -o custom-columns=NAME:.metadata.name,READY:.status.readyReplicas,IMAGE:.spec.template.spec.containers[0].image echo "pod phase: $(kubectl -n demo-kubectl get pods -l app=web -o jsonpath='{.items[0].status.phase}')" kubectl explain deployment.spec.replicas | sed -n '/DESCRIPTION/,$p' | head -3

NAME READY IMAGE web 1 nginx:1.29-alpine pod phase: Running DESCRIPTION: Number of desired pods. This is a pointer to distinguish between explicit zero and not specified. Defaults to 1.

Test yourself

Why prefer kubectl apply -f over kubectl edit for production changes?

apply is faster

Files in Git are reviewable, repeatable and recoverable; edits are not

edit is deprecated

apply works offline

Show answer

Answer: Files in Git are reviewable, repeatable and recoverable; edits are not

Declarative files are the source of truth that GitOps and reviews rely on.